[R] Simple Nesting question/Odd error message

[Jarrett Byrnes]

I'm attempting to analyze some survey data comparing multiple docks.  I 
surveyed all of the slips within each dock, but as slips are nested 
within docks, getting multiple samples per slip, and don't really 
represent any meaningful gradient, slip is a random effect.  There are 
also an unequal number of slips at each dock.

I'm having syntactical issues, however.  When I try

dock.lme<-lme(X.open ~ Dock, random=Slip|~Dock, data=my.data)

I get

Error in inherits(object, "reStruct") : Object "Slip" not found

I'm uncertain as to what this means, as Slip most certainly is there 
(yes, I checked) - any pointers, or pointers about syntax for this as a 
general topic.

And while I'm on it, is there a way to fit models with random effects 
using least squares instead of REML?  Thanks!

-Jarrett